Sprinkler alarm mechanism



Oct. 29, 1935. c. P. HOWARD SPRINKLER ALARM MECHANISM File i Jan. 29, 1934 Z rcr ivy-z Patented Oct. 29, 1935 UNITED STATES PATENT OFFICE SPRINKLER ALARM MECHANISM chusetts Application January 29, 1934, Serial No. 708,879

2 Claims.

This invention relates to sprinkler systems used for fire protection and more particularly to alarm mechanism used in connection therewith. When one or more sprinklers open, it is most desirable that an alarm be sounded so that aid may be quickly available to assist in extinguishing the fire and to prevent unnecessary water damage.

It is the object of my present invention to provide an improved and simplified mechanism for such alarm purposes, which mechanism is of general utility but is particularly designed for smaller sprinkler installations.

A more specific object of my invention is to provide a sprinkler alarm mechanism in which convenient provision is made for controlling the time interval between the opening of a sprinkler head and the sounding of an alarm. Excessive variations in water supply or operating pressures make such provision very important.

My invention further relates to arrangements and combinations of parts which will be hereinaiter described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawing, in which Fig. 1 is a side elevation, partly in section, of my improved alarm mechanism;

Fig. 2 is a sectional plan view of certain parts, taken along the line 2-2 in Fig. 1;

Fig. 3 is an enlarged sectional side elevation of a valve forming an important part of my invention, and

Figs. 4 to 8 inclusive are detail views of separate parts 01' the valve mechanism.

Figs. 9 and 10 are detail views of a filtering P us.

Referring to the drawing, I have shown a pipe l2, the open left-hand end of which is presumed to be connected to the main valve of an automatic sprinkler system. This main valve, or an auxiliary check valve associated therewith, opens as soon as the opening of a sprinkler head causes a substantial reduction in pressure in the sprinkler system.

As soon as the main or auxiliary valve opens, water flows into the system to supply the open sprinkler head, and a portion of this water flows along the pipe l2 to operate the alarm mechanism. The pipe I2 is preferably connected to ports in the seats of the main and auxiliary valve, which ports are closed when the valves are closed.

I have shown my improved alarm mechanism as comprising certain parts mounted within a casing l6 (Fig. 1) and supported on a retarding chamber l6 attached to the upper end of a valve casing 20, the lower portion of which may be threaded into a pipe fitting or T 2| to which the pipe I2 is connected.

A branch pipe 24 extends beyond the T 2| and is provided with a drip or vent pipe 26 and with a ball check valve 21. Under normal conditions, the ball 28 occupies the position shown in Fig. 1, with the vent pipe 26 open to take care of any leakage into the pipe l2 through the main or auxiliary valves. water occurs, however, the ball 28 will be pressed against the end of the vent pipe 26, thus substantially sealing the branch pipe 24.

It is desirable, however, that the seat for the ball 28 be scored or grooved, so as to prevent absolutely tight closure of the valve 21. This permits the water in thepipe l2, chamber l5 and other associated parts to drain away slowly after the valves in the main supply pipe are closed. Atmospheric pressure is thus admit-ted to the pipe l2. Otherwise, pressure might be built up or retained in the pipe l2 which would have a tendency to unseat the main or auxiliary valve.

The valve casing contains a check valve of the ball type which controls the fiow of water into the retarding chamber l6. A ball 30 is loosely confined within the casing 20, being limited in movement in one direction by a partition having a conical valve port 3| therein, and

in the opposite direction by a screen 32 mounted u in a threaded bushing or nut 33.

A nut 35 is threaded into the valve casing 20 above the partition 3| and is provided with a downwardly projecting stud 36 and with a screwdriver slot 31 (Fig.6). Axial passages 38 (Figs. 3 and 7) are also provided at each side 01 the slot 31 and stud 36.

It is obvious that the passages 38 allow a flow of liquid therethrough at all times in either direction, regardless of the adjusted position of the nut 35. The nut is so adjusted that the stud 36 engages the ball 30 as shown in Fig. 3 before the ball is closely seated in the port 3|. Complete closing of the check valve is thus prevented. The amount of valve opening may be regulated by screwing the nut 35 into or out of the casing 26. A check nut 39 may be provided to preserve the desired adjustment.

When water is flowing into the retarding chamber l6, the rate of fiow will be determined by the position of the ball 30, which position is in turn dependent on the adjustment of the nut 35 and stud 36. Downward flow out of the chamber l6 will be relatively free at all times, as the ball 30 then drops down and rests on the screen 32.

If any substantial flow of The upper end of the retarding chamber I 5 is closed by a diaphragm 49 held in place by a cover plate 4| on which suitable switch-reversing mechanism is mounted. In the drawing, I have shown this switch as similar in construction to that shown in the prior patent to John F. Carlson and myself, No. 1,932,784, issued 00- tober 31, 1933.

Briefly described, this mechanism comprises a casing 43 mounted on the cover plate 4| and providing an axial guideway for a plunger 44 secured at its lower end to the diaphragm 40 and normally pressed downward by a spring 45. The plunger 44 actuates a bent lever 45 having a portion 41 alternately engaging opposite ends of a rocking lever 48 mounted on a short shaft 49 pivoted in a post extending upward from the casing 43.

Mercury switch elements 59 (Fig. 2) may be mounted at opposite ends of the pivot shaft 49 which supports the rocking member 48. As the member 49 and shaft 49 are rocked, one or more suitable electric circuits may be opened or closed by the mercury switch elements 50, such shifting of the switches being effective to cause an alarm to be sounded over either public or private fire alarm circuits.

Whenever pressure is built up in the chamber l6 suflicient to overcome the pressure of the spring 45, the plunger 44 will be moved upward, shifting the bent lever 46, reversing the rocking member 48, and shifting the switch elements 59 to cause an alarm.

As soon as the main and auxiliary valves in the main supply pipe are both closed, water begins to leak out through the scored seat of the check valve 21, thus relieving the pressure in the chamber I5 and discontinuing the alarm. The ball 29 then drops back, permitting more rapid drainage.

The chamber I6 is normally empty and at atmospheric pressure, being then connected to the vent pipe 26, and a considerable flow through the valve in the valve casing 20 must take place before a pressure will be built up in the casing I 6 suiiicient to overcome the spring 45.

As previously described, the rate of flow into the chamber I6 is controlled by the setting of the screw 35 relative to the valve seat or port 3|. As the amount of water passing through a given valve opening varies with the pressure, it

is obvious that a greater minimum valve opening is necessary for low pressures and a less opening for higher pressures. Such adjustment is readily accomplished by removing the casing 20 from the chamber l6 and changing the setting 01' the screw 35.

In the case 01 water hammer, only very small portions of the water passing the main valve can find their way through the restricted port opening of the check valve in the casing 20. As soon as the hammer impulse passes, the water again flows out through the vent pipe 26. Consequently water due to water hammer does not accumulate in the retarding chamber IE to a suiilcient extent to sound an alarm.

It will be noted that all parts of my improved alarm mechanism are simple and inexpensive and that they are so designed that they will be extremely reliable under all operating conditions.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. Sprinkler alarm mechanism comprising a retarding chamber, a diaphragm closing one side 01 said chamber, switch mechanism controlled by said diaphragm, a connection from the sprinkler system. to said retarding chamber, a retarding check valve in said connection providing restricted flow of water to said chamber and relatively free flow from said chamber, a vent for said connection below said retarding valve, a check valve for said vent. andmeans to provide restricted flow past said latter check valve to the atmosphere.

2. Sprinkler al'arm mechanism comprising a retarding chamber, a diaphragm closing one side of said chamber, switch mechanism controlled by said diaphragm, a connection from the sprinkler system to said retarding chamber, a retarding check valve in said connection providing restricted flow of water to said chamber and relatively free flow from said chamber, a vent for said connection below said retarding valve, a vent valve opening toward said retarding valve and providing free access 01' air to said connection when said vent valve is open, and means permitting restricted flow of water past said vent valve to the atmosphere when said vent valve is seated.

CLIFTON P. HOWARD. 

